Pen



FIG. 1 is a perspective view of a pen showing my new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a bottom plan view;

FIG. 5 is a left end elevational view thereof;

FIG. 6 is a right end elevational view thereof; and

FIG. 7 is a rear elevational view thereof.

The ornamental design for a pen, as shown.